I think a mix of manure(s) and other organic matter would work better than either one alone. This would help with the salt issue, too. It is critical that there is actually soil above the rock, otherwise there is nothing for the roots to grow in.
The other issue is that you're not re-creating a former plant community that was destroyed by over-grazing or other human activity. You are trying to create a plant community that never existed in that location due to insufficient rainfall. Take a portion of your yard that has the best soil, improve that area and let the rest of it be what it was or add exotics that can survive on the existing rainfall or with minimal additional irrigation. It's much less stressful.
